Compilare: user.cpp: In function ‘int main()’: user.cpp:28:21: warning: unused variable ‘xi’ [-Wunused-variable] int n , x , y ,xi[251],yi[251],a=1,b=1,c; ^ user.cpp:28:29: warning: unused variable ‘yi’ [-Wunused-variable] int n , x , y ,xi[251],yi[251],a=1,b=1,c; ^ user.cpp:28:41: warning: unused variable ‘b’ [-Wunused-variable] int n , x , y ,xi[251],yi[251],a=1,b=1,c; ^ user.cpp:28:45: warning: variable ‘c’ set but not used [-Wunused-but-set-variable] int n , x , y ,xi[251],yi[251],a=1,b=1,c; ^